SiO2 film thermal

The dielectric properties of the SOG films cured at 400°C are, in general, inferior to those of thermal SIO2 or low temperature CVD SIO2 films. The high dielectric constant of 203 indicates the presence of a significant amount of polarizable material in the SOG film. This polarizable species is H2O that is adsorbed into the micropores of the film, the adsorption being facilitated by presence... 

Figure 15.24 shows the fabrication process of the optical filter on a fluorinated polyimide substrate. First, the low-thermal-expansion-coefficient PMDA/TFDB poly(amic acid) solution was spin-coated onto a Si substrate and baked. Then alternate TiO2 and SiO2 layers were formed on the polyimide film by ion-assisted deposition. The multilayered polyimide film was diced and peeled off from the Si substrate. In this way, thin optical filters on a fluorinated polyimide substrate are easily fabricated. 

Si wafers of n-type and (100) orientation covered by thermally grown 100 nm SiO2 layer fabricated at 1100 °C in dry O2, were used as substrates. The wafers were loaded into an oil free evaporation chamber (Varian VT-460), and the system was evacuated down to lxlO 8 Torr. Ge ingot of 99.999 % purity was supported on a molybdenum plate, and it was evaporated using an electron gun, at an evaporation rate of 0.01-0.03 nm/s, at a pressure of lxlO"7 Torr. During evaporation, and for an additional 1 min after this process, the substrate temperature was kept at 350 °C. The temperatures were monitored by small-heat-capacity Ni-NiCr thermocouples, while the film thicknesses were measured by a vibrating quartz probe. For this study, four different samples have been prepared with different Ge evaporation times of 25, 50, 75, and 100 s for samples No. 1, 2, 3, and 4, respectively. After germanium evaporation, the samples were moved to a cold place inside the vacuum chamber. 

There is universal agreement that the rate of thermal oxidation of silicon decreases as the SiO film grows(4-6). It has been established that the oxidation reaction that produces SiO2 occurs at the Si-SiO2 interface(7-9). From all the available information, the SiO2 formed in an impurity free environment at... 

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